Showing papers on "Voltage multiplier published in 1998"

Corona discharge device for destruction of airborne microbes and chemical toxins

Abstract: A miniature air purifier produces a corona discharge surrounding a needle-like emitter point connected to a negative DC power supply. The power supply operates from a nine volt battery and contains a step-up voltage inverter having a single transformer outputting high voltage spikes with a voltage multiplier operating on the output of the inverter. The production of high voltage spikes of about 200 Hz rather than a sinusoidally varying voltage significantly reduces current consumption. The needle-like emitter point is located about 1/4-inch from an 80% open mesh metallic grid held at ground potential. Corona discharge at the emitter point ionizes the air and creates ozone, and nitric oxide both of which combine with direct electron impact decomposition to detoxify and destroy a wide variety of airborne pollutants including pathogens, chemicals and allergens. The grid attracts negatively ionized air molecules thereby creating a flow of purified air out of the device and also provides a surface for electroprecipitation of ionized particulates. An alternative embodiment of the present invention can combine a series of emitter points in a sterilizer to provide a microbial neutralization in the food service industry.

Voltage booster for enabling the power factor controller of a LED lamp upon low ac or dc supply

Abstract: The light-emitting-diode lamp comprises a set of light-emitting diodes, a rectifier and power converter circuit, and a power factor controller. The rectifier and power converter circuit converts ac or dc voltage and current from a power source to dc voltage and current supplied to the set of light emitting diodes. The rectifier and power converter circuit includes an electronic switch through which it is supplied with ac or dc voltage and current from the power source, and an inductor device including windings adapted to charge a capacitor with a voltage signal representative of the amplitude of the ac or dc voltage from the power source. The power factor controller is responsive to the voltage signal across the capacitor for controlling the electronic switch of the rectifier and power converter circuit in view of supplying dc voltage and current to the set of light emitting diodes while maintaining the power factor of the light-emitting-diode lamp equal to or close to unity. The power factor controller comprises a voltage comparator supplied with the voltage signal across the capacitor for enabling operation of the power factor controller as long as the ac or dc voltage from the power source has an amplitude higher than a first predetermined voltage threshold. A voltage boosting circuit raises the amplitude of the voltage signal across the capacitor when the ac or dc voltage from the power source is lower than the first voltage threshold to keep operation of the power factor controller enabled as long as the ac or dc voltage is higher than a second predetermined voltage threshold lower than the first predetermined voltage threshold.

A novel power converter with voltage-boosting capacitors for a four-phase SRM drive

Abstract: This paper presents a method of enhancing the performance of a four-phase switched reluctance motor by using capacitors to produce additional supply voltage during the rise and fall periods of motor phase current. The voltage rating of the inverter components increases and extra capacitor/diode combinations are needed. The operation and analysis of a series voltage boost circuit are detailed for different modes of operation with a study of the effect of the boost capacitor voltage on the current waveform. Different voltage boost circuit configurations are compared. The predicted and measured results show that the boost circuit increases both torque and output power and improves the efficiency of the machine, especially at high speeds.

Active series switch for switched-opamp circuits

Abstract: A series switch to be used in switched-opamp circuits is proposed. The circuit can be implemented in standard CMOS technology and allows rail-to-rail input and output signals to be processed without a voltage multiplier. Using a 0.5 /spl mu/m CMOS technology, with a 1 V supply, the circuit exhibits a total harmonic distortion better than -60 dB for a differential signal amplitude up to 1.8 Vpp.

Non-contact IC card with monitor for source power

Abstract: A non-contact type IC card includes a rectifier circuit for supplying a source voltage to respective circuits of an IC card based on the strength of radio waves received from a host computer. A reference voltage generating circuit generates a reference voltage. A comparison circuit compares the source voltage with the reference voltage. A control circuit prohibits the writing of data if the source voltage becomes less than the reference voltage.

Rapid on chip voltage generation for low power integrated circuits

Abstract: An on chip voltage generation circuit is provided suitable for use on integrated circuits such as flash memory devices with a low power supply voltage (e.g., 2.7 to 3.6 volts). A voltage boost circuit is coupled to the supply voltage input and to a boost signal, which boosts the on-chip voltage at a node on the integrated circuit in response to a transition of the boost signal. The voltage boost circuit has a first mode which in response to the transition boosts the on-chip voltage at a first rate of boosting until a first threshold, and a second mode which in response to the transition boosts the on-chip voltage at a second rate of boosting until a second threshold. The second rate of boosting in the preferred system is slower than the first rate of boosting. A detection circuit is coupled to the node on the integrated circuit which receives the on-chip voltage, and to the voltage boost circuit. The detection circuit signals the voltage boost circuit when the node reaches the first threshold, and signals the voltage boost circuit when the node reaches the second threshold. According to one aspect of the invention, the first threshold is reached within less than 5 nanoseconds, and more preferably about 2 nanoseconds, or less, of the transition in the boost signal.

Process and circuit layout for using an independent capacitor for the momentary retention of an output voltage when an input voltage is lost

Abstract: Process and circuit layout for using an independent capacitor for the momentary retention of an output voltage when an input voltage is lost. To facilitate a reduction in capacitance in independent circuits of this type at a constant amount of charge, the input voltage is transformed by a DC/DC up converter to a higher capacitor voltage, which is stored in the independent capacitor and the capacitor voltage is transformed by a DC/DC down converter to the output voltage for the load element, which is less than the capacitor voltage. As the DC/DC down converter can utilize capacitor voltages until the output voltage is reached, the residual voltage remaining in the independent capacitor (C) is no longer used. The independent time interval is correspondingly short. According to the invention, the capacitor is disconnected from the output of the DC/DC up-converter and connected to its input when the input voltage is less than a reference voltage. In the situation while the capacitor voltage is connected to the input of the DC/DC up converter, this converter can step-up the capacitor voltage, which drops during the independent time interval, and retain a virtually constant voltage at the output, which the DC/DC down converter then transforms to the output voltage. The independent capacitor can discharge more deeply and the independent time interval can be perceptibly extended. The process and circuit layout are particularly suitable for supplying electronic assemblies in vehicles, as these start from a relatively low input voltage, which is particularly advantageous for the use of DC/DC converters.

Magnetically compatible peripheral nerve stimulator

Abstract: The present invention provides a peripheral nerve stimulator (10) of low magnetic susceptibility that can be used in the high magnetic field of an MRI suite. Non-magnetic lithium batteries power the peripheral nerve stimulator. A stack of capacitors, and diodes (hereinafter 'components') forming a voltage multiplier (20) replace the conventional step-up transformer. Each component is carefully chosen for low content of the magnetic materials. To minimise the number of components, and enable the magnetically compatible peripheral nerve stimulator to be a handheld instrument, a full H bridge supplies power to the multiplier. The power is an AC signal with voltage equal or plus or minus to the supply voltage. This provides a peak to peak voltage value of two times the available battery voltage. This approach reduces the number of capacitors, and diodes to half compared to the half bridge solution.

Closed-loop switched capacitor network power supply

Abstract: A closed-loop switched capacitor power supply converts a supply voltage into an output voltage that rapidly approaches a set-point voltage by using a variable frequency source, a switched capacitor network and a feedback control circuit. The variable frequency source provides the switched capacitor network with a control voltage having a control frequency that affects the impedance of the switched capacitor network. The switched capacitor network comprises one or more network sections, each one having a grounded capacitor with the other terminal coupled to a supply voltage through a first switch and coupled to the load through a second switch. The first and second switches work in a complementary manner, such that when the first switch is closed the capacitor is charged by the supply voltage, and when the second switch is closed the capacitor discharges into the output of the switched capacitor network. The feedback control circuit is coupled to the output of the switched capacitor network and uses a proportional integral/derivative compensator to regulate the control frequency of the variable frequency source in accordance with the difference between the output voltage and the set-point value. In this way, the output voltage of the power supply can be controlled by varying the frequency of the control voltage of the variable frequency source. Embodiments with additional capacitor networks are advantageous as output ripple is reduced and the overall energy efficiency of the circuit is increased. The power supply is also capable of measuring the power consumption of the load with high accuracy.

High efficiency charge pump circuit for negative high voltage generation at 2 V supply voltage

Abstract: A charge pump circuit has been developed for the generation of negative high voltage at supply voltage levels down to 2V. The generated high voltage is suitable for programming Flash EEPROM cells, that use Fowler-Nordheim tunneling. The key issue of the circuit design has been high efficiency and small chip area. The circuit consists of n-MOS transfer gates in a triple-well structure and is driven by a four phase clocking scheme. The power efficiency of a charge pump, designed for low power applications, is better than 25% at an output power of 100µW, including clock generation and voltage regulation.

About the DC-link capacitors voltage balance in multi-point clamped converters

Abstract: The multi-point clamped converter (MPCC) represents an interesting technical solution to overcome the limitations in voltage and power posed by the existing semiconductor devices. However, if real power must be delivered to the load, DC-link capacitors exhibit a problematic voltage unbalance, that can be faced in both active or passive ways, that is, by using or not using additional components. Both approaches can be used together, in order to optimize the system performances. The authors have analyzed this problem from an analytical point of view and have developed a modulation control strategy that exploits the inherent redundancy in switching configurations to achieve a correct voltage sharing, in the case of a MPCC with four DC-link capacitors. The results obtained are presented and discussed in a critical way and they are correlated to the case where an active rectifier is used as an input stage to achieve near unity power factor and capacitors voltage balance.

Power supply unit with built-in electric double-layer capacitor

Abstract: PROBLEM TO BE SOLVED: To provide a power supply unit with built-in electric double-layer capacitors wherein the safeties to their overchargings and dischargings are considered thoughtfully and their instantaneous charging or discharging currents are made large. SOLUTION: A voltage sensing portion 11 senses the voltage applied across positive and negative terminals 5A, 5B of electric double-layer capacitors 1 connected in series with each other. The voltage applied across the terminals 5A, 5B or the electric double-layer capacitors 1 is increased when the capacitors 1 are charged excessively. A voltage comparing portion 19 decides whether the voltage applied across the terminals 5A, 5B exceeds an upper limit voltage or not. In the meantime, the voltage applied across the terminals 5A, 5B of the electric double-layer capacitors 1 is decreased when the capacitors 1 are discharged excessively. A voltage comparing portion 15 decides whether the voltage applied across the terminals 5A, 5B drops beyond a lower limit voltage or not. The comparison results of the voltage comparing portions 19, 15 are sent to a control portion 21 of a charge/discharge limiting switch 7 to perform the ON/OFF of the switch 7. COPYRIGHT: (C)2000,JPO

System for concurrent digital measurement of peak voltage and rms voltage in high voltage system

Abstract: A voltage measurement system is provided which concurrently measures peak voltage and root mean square voltage. The voltage measurement system employs a digital peak detection circuit (22) for peak voltage measurement. The voltage measurement system employs a memory device (24) for storing sample of a voltage signal at predetermined intervals corresponding to a line frequency multiplication factor. The samples in the memory device are then used to calculate root mean square voltage.

Method and apparatus for maintaining a high voltage capacitor in an implantable cardiac device

Abstract: An implantable cardiac device incorporating a processor and a waveform generation circuit incorporating a high voltage capacitor wherein the processor is adapted to charge the capacitor to an initial voltage, less than the peak voltage, and then measure the leakage current occurring across the capacitor at the initial voltage. If the leakage current occurring across the capacitor at the initial voltage is less than a preselected value, selected so that the corresponding leakage current across the capacitor when the capacitor is charged to the peak voltage is within an acceptable tolerance range, the processor then does not perform any further reforming of the capacitor. Alternatively, if the leakage current across the capacitor at the initial voltage is greater than the preselected value, even the processor is adapted to charge the capacitor to a higher voltage, such as the peak voltage, and retain the capacitor at the higher voltage so that the capacitor may be reformed as a result of the application of the higher voltage.

Semiconductor device reducing voltage consumption in voltage-detection circuit

Abstract: A semiconductor device consuming a first voltage includes a voltage-detection circuit which detects a voltage level of the first voltage, and a control circuit which controls the voltage-detection circuit to operate for a predetermined time period in accordance with a timing at which the first voltage is started to be consumed.

Gas discharge lamp inverter with a wide input voltage range

Abstract: A gas discharge lamp driving circuit reduces input power at start-up mode through the utilization of input power diodes and stress capacitors in parallel therewith. The circuit includes a blocking filter for filtering an AC voltage signal, and a rectifier for rectifying the signal into a DC voltage. A smoothing capacitor smooths the voltage, and an inverter, having switches, converts the DC voltage into a high frequency AC voltage. A control circuit controls the switches of the inverter to turn on and off in a feedback manner. A resonant tank is connected to the inverter, and includes a resonant capacitor and a resonant inductor. A discharge lamp is connected to the resonant tank, in parallel with the resonant capacitor. A modulation capacitor is provided for reducing a distortion of the input current to the resonant circuit. The at least two input power diodes and the stress capacitors are connected between the rectifier and the smoothing capacitor, such that a discharge time of the stress capacitors delays a turn-on time of the input power diodes, to reduce input power at start-up.

Multiple flash/single lamp circuit for fast sequential strobing

Abstract: The present invention discloses a multiple flash/single lamp circuit for fast sequential strobing. More particularly, the present invention comprises a flashlamp, a pair of capacitors, a voltage multiplier and regulator to charge the capacitors, a pair of trigger circuits to discharge the capacitors and a controller to selectively activate each trigger circuit to activate the flashlamp.

DC power supply apparatus including boosting/lowering converter unit and control

Abstract: An input-side rectifier of a DC power supply apparatus receives and rectifies an AC voltage selected from first and second groups of AC voltages. The AC voltages in the second group are lower than those of the first group. A voltage boosting/lowering converter boosts or lowers the output voltage of the input-side rectifier to a voltage having a predetermined value. An inverter converts the output voltage of the voltage boosting/lowering converter to a high-frequency voltage. A voltage transformer transforms the high-frequency voltage from the inverter. An output-side rectifier rectifies the transformed high-frequency voltage from the transformer.

High voltage generation circuit which generates high voltage by digitally adjusting current amount flowing through capacitor

Abstract: A high voltage generation circuit includes an inductor, a PN diode, a capacitor and a transistor. A high voltage sampling/division circuit, a control register, a voltage comparator, a counter, a pulse generation circuit and a ring oscillator in the high voltage generation circuit detect whether voltage generated through the capacitor is a desired high voltage or not and generates a pulse signal which controls ON/OFF of the transistor. Accordingly, a path of current flowing into the capacitor is changed and the generated voltage is digitally adjusted.

Method and circuitry for high voltage application with MOSFET technology

Abstract: A method and apparatus for high voltage applications, with the latest MOSFET technology having limited terminal-to-terminal voltage capability, includes a switch circuit having at least two serially coupled MOSFETs and a two-stage MOSFET connection using a plurality of resistors, and/or a bipolar transistor, and a plurality of diodes. One of the high voltage applications is a high speed write driver in a computer disk drive. The switch circuit switches on/off between zero volt and a voltage higher than a maximum terminal-to-terminal voltage of a single MOSFET which is typically five volts. A required voltage in high voltage applications can be in excess of, for example, 8 or 9 volts.

A DC-AC converter using a voltage equational type switched-capacitor transformer

Abstract: A new type DC-AC converter using a voltage equational type switched capacitor transformer is presented. A test circuit which converts DC voltage (160 V) to an AC voltage (100 V/60 Hz) was built. The experimental results of the prototype DC-AC converter show that the efficiency is very high (98%) and its output power is large (300 W).

Control device for capacitor

Abstract: PROBLEM TO BE SOLVED: To reduce the number of circuits by constituting basic breakdown voltage differential amplifiers, so that the voltages of capacitors are converted relative to the lowest negative terminal of a unit row of the capacitors and are input to a low-breakdown voltage circuit. SOLUTION: In a device, four capacitors 101 are series-connected to form a unit row 102 of the capacitors, and the unit row 102 of the capacitors is connected with a low-breakdown voltage circuit 106, provided with power from a low-voltage source 108, via a basic breakdown voltage circuit 105. The basic breakdown voltage circuit 105 contains a four basic breakdown voltage differential amplifiers 107, and the power supplies to the basic breakdown voltage differential amplifiers 107 are all connected with the highest positive terminal 103 and the lowest negative terminal 104. The basic breakdown voltage differential amplifiers 107 convert the voltage between terminals of each of the capacitors 101, different in potential level, relative to the potential level of the lowest negative terminal 104, and these outputs are connected with the low-breakdown voltage circuit 106, respectively. As a result, since the detected voltage between terminals is processed through the common low-breakdown voltage circuit 106, the number of circuits can be reduced. COPYRIGHT: (C)2000,JPO

Extending battery life in electronic apparatus

Abstract: An electronic apparatus such as a digital wide area pager has a receiver IC (10) capable of operating directly from a single cell battery (24) for as long as the terminal voltage (VBAT) is above a specified minimum voltage. Other ICs (14, 16) of the pager operate at a higher voltage supplied by a multiplier (26) connected to the battery (24). The multiplier (26) is able to operate at values of VBAT below the specified minimum voltage. A control circuit (34) determines when the terminal voltage (VBAT) decays below the specified minimum voltage and supplies the receiver IC (10) with a stepped-down voltage from the multiplier (26) to ensure its sensitivity remains acceptable.

Dimmable ballast with active power feedback control

Abstract: A circuit arrangement for high-frequency operation of a discharge lamp comprises a low-frequency rectifier for generating a DC voltage (buffer voltage) across a first capacitor (C1) from a low-frequency supply voltage. A DC/AC converter generates a high-frequency AC voltage from the buffer voltage. A load branch is coupled to the DC/AC converter and is provided with coupling terminals for coupling the discharge lamp to the load branch. A high-frequency rectifier (HR) converts the high-frequency voltage generated by the DC/AC converter into a DC voltage and comprises a series arrangement of first and second diodes (D5, D6) which have the same orientation. A control circuit (CR) controls the power consumed by the discharge lamp to a level which is dependent on a control signal (Sg). The high-frequency rectifier further comprises a switching device and a further control circuit (CR1). The switching device shunts at least one of the diodes of a feedback unit. The further control circuit controls the switching device dependent on the control signal.

Liquid crystal back light illuminating device and liquid crystal display device

Abstract: A liquid crystal back light illuminating device includes a driving circuit which receives a first value voltage at light-on starting. The device drives a voltage stepping up circuit and lights on a cold cathode tube with a stepped-up high voltage. Thereafter, it receives a second value voltage, drives the voltage stepping up circuit and continues the lighting-on of the cold cathode tube with a lower stepped-up voltage than the former stepped-up high voltage. A slowly varying voltage which is obtained by charging a capacitor with a small current is applied to the driving circuit via an amplifier and a switch circuit. When the varying output voltage comes close to the second value voltage beyond a predetermined value, the switch circuit switches to the second value voltage. Thereby, flickering of the cold cathode tube at the time of switching the light-on condition is prevented.

Voltage multiplier with low threshold voltage sensitivity

Abstract: A voltage multiplier has a number of electrically-like stages. Each of the stages receives two input signals and a pump signal. The stage has an MOS transistor with a first source/drain region and a second source/drain region and a gate. Each stage also has means for receiving a pump signal and for separately pumping the first source/drain region and the gate of the first transistor by the pump signal. The two input signals are supplied to the first source/drain region and the gate of the first transistor, respectively. A first output signal is supplied from the second source/drain region of the first transistor, and from the first source/drain region of the first transistor. A voltage signal is supplied as the input signal of the first stage and a clock signal having a first phase is supplied to the first stage as the pump signal of the first stage. The first and second output signals of the first stage are supplied to the second stage as the input signals of the second stage and a clock signal having a second phase different from the first phase is supplied to the second stage as the pump signal of the second stage.

Protection circuit against electrostatic charge applied between power supply terminals for preventing internal circuit therefrom regardless of polarity thereof

Abstract: Voltage clamping elements are respectively paired with first diodes, and the pairs of voltage clamping elements/first diodes are connected between a first common discharge line and power terminals selectively supplied with positive power voltage and ground voltage; however, the pairs of voltage clamping elements/first diodes can not prevent an internal circuit from excess voltage if a positive electrostatic pulse with respect to the positive power voltage is applied to the ground terminal; second diodes are connected between a second common discharge line and the terminals in such a manner as to discharge the positive electrostatic pulse through the associated forward-biased second diodes, and the internal circuit is perfectly prevented from the excess voltage.

Circuit generator of a constant electric signal which is independent from temperature and manufacturing process variables

Abstract: A circuit for the generation of an electrical signal of constant duration comprises a capacitor, a constant current generator for charging the capacitor, and a voltage comparator to compare the voltage present at the terminals of the capacitor with a reference voltage. The voltage comparator supplies at an output a digital signal dependent upon the voltage across the capacitor. The constant current generator comprises a transistor biased with a voltage between gate and source obtained as the difference between the sum of two gate-source voltages of two transistors and a gate-source voltage of another transistor.

A 1.8 V low-power CMOS high-speed four quadrant multiplier with rail-to-rail differential input

Abstract: A low-voltage (/spl les/3 V) CMOS four quadrant multiplier is introduced which has an almost rail-to-rail differential-input-swing with a low signal-distortion (/spl les/1% for 1 MHz signal, /spl les/7% for 100 MHz signal). The proposed circuit is composed of a pair of rail-to-rail differential-input V-I converters and a pair of voltage-followers. This topology of multiplier results in a high frequency capability with low power consumption. In a 1.2 /spl mu/m n-well CMOS process, the 3 dB frequency of the multiplier is in a range of 103 MHz. The total power consumption is around 0.5 mW with supply voltage 2 V. The multiplier can operate at a minimum supply voltage of 1.8 V.

Accelerated degradation of capacitor PP films under voltage distortion

Abstract: The effect of voltage distortion, that is, of nonsinusoidal supply voltage, on aging acceleration of PP films for ac capacitors is here investigated. The voltage endurance of PP films subjected to life tests under various combinations of sinusoidal and distorted voltage is derived as function of characteristic parameters of the supply-voltage waveform, i.e. peak and rms voltage, as well as waveshape slope. Life tests are performed in oil, in the absence of significant partial discharges, in order to focus the investigation on intrinsic aging. Comparisons are made with the results obtained for low-voltage capacitors. It is shown that for both capacitors and PP films, the prevailing degradation accelerating factor is voltage-peak amplification.